Are those in present day Jerusalem the children of Hagar?

In Galatians 4:25, it seems to suggest that Jerusalem is in slavery with Hagar because they are her children. Can you please explain?

In Galatians 4 Paul makes the following statement:

Gal. 4:25 Now this Hagar is Mount Sinai in Arabia and corresponds to the present Jerusalem, for she is in slavery with her children.
Gal. 4:26 But the Jerusalem above is free; she is our mother.
Gal. 4:27 For it is written,
   “Rejoice, barren woman who does not bear;
   Break forth and shout, You who are not in labor;
   For more numerous are the children of the desolate
   Than of the one who has a husband.”
Gal. 4:28 And you brethren, like Isaac, are children of promise.
Gal. 4:29 But as at that time he who was born according to the flesh persecuted him who was born according to the Spirit, so it is now also.
Gal. 4:30 But what does the Scripture say?
   “Cast out the bondwoman and her son,
   For the son of the bondwoman shall not be an heir with the son of the free woman.”
Gal. 4:31 So then, brethren, we are not children of a bondwoman, but of the free woman.

Paul taught an allegory from the account of Sarah sending away Hagar and Ishmael. In the allegory Hagar represents the nation of Israel under the Law awaiting freedom in Christ. Just as Hagar was a servant of Sarah and in bondage to her, so is Israel in bondage under the Law, as Paul taught in the beginning of Galatians 4:

Gal. 4:1 Now I say, as long as the heir is a child, he does not differ at all from a slave although he is owner of everything,
Gal. 4:2 but he is under guardians and managers until the date set by the father.
Gal. 4:3 So also we, while we were children, were held in bondage under the elemental things of the world.
Gal. 4:4 But when the fullness of the time came, God sent forth His Son, born of a woman, born under the Law,
Gal. 4:5 so that He might redeem those who were under the Law, that we might receive the adoption as sons.
Gal. 4:6 Because you are sons, God has sent forth the Spirit of His Son into our hearts, crying, “Abba! Father!”
Gal. 4:7 Therefore you are no longer a slave, but a son; and if a son, then an heir through God.

Therefore, "the present Jerusalem” of Galatians 4:25 refers to the Israel that is under the Law, which is every Jew who has not yet placed their faith in Jesus Christ. Pastor Armstrong echoes Paul’s teaching on this point as he correctly stated that the present Israel is in bondage under the Law. What was true for the Israel of Paul’s day remains true for the Israel of today. Only by being born again through faith in Jesus Christ may a Jew be freed from this bondage, as Paul implies in his allegory in vs.26-29.

Those who have come to faith in Jesus Christ are children of the promise, as was Isaac. They are born according to the Spirit, and as such they overcome those born according to the flesh.

To suggest that present-day Jerusalem is descended from Hagar is to confuse the allegory with reality. In an allegory, each literal figure (i.e., Sarah, Hagar, etc.) stands for something. In this allegory, Hagar stands for the bondage under the Law, and therefore Pastor Armstrong said that present-day Jerusalem is also like Hagar because unbelieving Jews today are under the same bondage to the Law as the Jerusalem of Paul’s day.